Teased in a Twitter post, LucasArts has officially announced what they meant by an "old school" game announcement. As it turns out, they publisher is finally allowing some of their classic PC games to be made available via download from Valve's Steam service.

The service will begin with 10 titles that will be added to Steam beginning Wednesday in what is descibed as the "first round" of LucasArts games to be made available on Steam. So if your favorite game isn't listed it's likely that it will be added to the Steam service at a later date. Further additions will be announced, natch, via LucasArts' Twitter page. Here's the full list of the first round of releases and some more info on their plans can be found at our sister site Joystiq.

• Armed and Dangerous
• Indiana Jones and the Fate of Atlantis
• Indiana Jones and the Last Crusade: The Graphic Adventure
• LEGO Indiana Jones: The Original Adventure
• LOOM
• Star Wars Battlefront II
• Star Wars Republic Commando
• Star Wars Starfighter
• The Dig
• Thrillville: Off the Rails

Update: For all you sticklers out there, according to Joystiq, the version of Indiana Jones and the Last Crusade: The Graphic Adventure that will be offered via Steam will actually be a "previously unreleased version". This version of the 1992 title will have "even more bugfixes" than the CD-ROM re-release.